THE BREAKFAST BRIEFING

Wait, maybe September isn’t that bad for stocks after all.

Wall Street strategists and the financial media (including yours truly) have written extensively about how poorly stocks typically perform in September, historically the worst-performing month of the year. But a closer look at recent data tells a vastly different story.

Stocks have risen in eight of the past 10 Septembers, with the lone outliers coming in 2008 (the worst of the financial crisis) and 2011 (the middle of the European debt crisis and one month after the downgrade of the U.S. credit rating).

Dan Greenhaus, chief strategist at BTIG, crunched the numbers and found that seasonal patterns are in the stock market’s favor not only for September but also for the rest of the year. Only twice since 1988 has the S&P 500 fallen in October. And the market has only had two down Decembers since 1982, according to his calculations.

“Don’t worry about September this year,” says Ari Wald, head of technical analysis at Oppenheimer & Co.

In a note to clients, Mr. Wald took an upbeat view on the September trade, noting that the worst September performances tend to occur when the market is struggling. When the market rises in the summer months, it tends to keep rallying into September.

Since 1950, the S&P 500 has averaged a 0.4% gain in September when the index has traded above its 200-day moving average at the end of August, according to Mr. Wald. By comparison, the index has averaged a 2.7% loss in the Septembers when it traded below the 200-day moving average.

The 200-day average is a chart line technical analysts use to define a market’s trend. When the S&P 500 is trading above this level, it is viewed as being in an upward trend. When it falls below, the market is considered to be in a downtrend.

The S&P 500 has traded above its 200-day moving average for 449 straight trading days, the fifth-longest streak in the index’s history, according to MKM Partners. The longest stretch ended in 1956, when the index spent 626 trading days above this chart line.

“Worries regarding weak September seasonals are overstated this year because the S&P 500 is in an uptrend,” Mr. Wald said.

Seasonal trends aside, concerns remain about the current state of the markets. Conflict in Russia and Ukraine as well as the Middle East can weigh on investors at any moment. And as we noted on Tuesday, September over the long term is still the weakest month for stocks. Since 1928 the S&P 500 has averaged a 1.02% decline in September and has been positive less than half the time, according to S&P Dow Jones Indices.

But over the past decade, September has been kind to the market. And given the performance of stocks this summer, September may not be as cruel as many have warned.

Morning MoneyBeat Daily Factoid: On this day in 1929, the blue-chip Dow Jones Industrial Average finished at 381.17. The closing level proved to be the Dow’s peak before the Crash of 1929 and the subsequent Great Depression. Stocks didn’t reclaim this level until 1954.

Liquidity Rules Coming to Wall Street: “U.S. regulators are opening a new front in their efforts to create a safer financial system with rules designed to ensure banks can survive a crisis without running out of cash.”

Banks’ Fee Bonanza Dries Up: “Banks are making less of their money from customer-account fees than at any time in the past seven decades as strict government rules and changing consumer behavior squeeze a major source of revenue.”

IEX to Apply for Exchange Status: “IEX Group, the upstart private trading venue that launched less than a year ago, plans within a week to seek U.S. regulatory approval to become a full-fledged stock exchange.”

FBI: No Evidence J.P. Morgan Breach Hit Other Banks: “The FBI hasn’t found any evidence to suggest the hacker or hackers who successfully penetrated the computer system at J.P. Morgan Chase & Co. scored any similar successes against other big U.S. banks, according to four people close to the investigation.”

Heard on the Street: Facebook 's Stock Too Popular for Its Own Good: “Nothing has diminished Facebook’s prowess in mobile advertising. But expectations and a high valuation may hold back its share price.”

Dollar’s Rally Picks Up Speed: “A two-month rally in the U.S. dollar picked up speed Tuesday on expectations the Federal Reserve could hike interest rates in the U.S. in the coming months while central banks elsewhere keep monetary policies loose.”